The present invention relates in general to braking and, more particularly, the invention relates to an apparatus for the measurement and/or regulation of a braking force and/or of a braking torque, which is transferred by a braking apparatus to a brakable element, in which the braking apparatus and the brakable element form a brake unit.
The problem of measuring and/or of regulating a braking force and/or a braking torque, comes up wherever it is necessary to retard components which are moving in relation to one another with the use of a brake apparatus. If the relative motion is translational, such as, in the movement of a machine sled on its bed, then the braking force is the measurement and/or regulatory characteristic. If the relative movement takes place along a curved path, such as, in the wheel brakes of motor vehicles with a constant radius of curvature, or cable drums; and with a changing radius of curvature, such as, on a carrousel, e.g. on a figure-eight railway, then the braking force can be tangential to the track and/or the product of the braking force and the radius of curvature, the braking torque, the measurement and/or control characteristic. Since, in the measurement and/or regulation of braking torque, the radius of curvature of the path is usually specified, the measurement and/or regulation of the braking torque also measures and/or regulates the braking force. But, since "braking force", on the other hand, is understood in important technical sectors as the deceleration force exerted on an entire unit, for example, a vehicle, the term "braking torque" will be used as a comprehensive designation for the concepts and particular situations described above.
An apparatus of the type described above is known in the art from I Mech E Conference Publications 1983-2: "Braking of Road Vehicles", specifically Paper C 22/83: "The development and proving of an individual wheel brake torque measurement system (IWBTM) for commercial vehicles", published by MEP Mechanical Engineering Publications Limited for the Institution of Mechanical Engineers, London. In this prior art, the deformations of a beam (axle body) of a wheel brake, serving as the brake unit of a vehicle under the influence of the braking torque, are monitored by means of strain gauges, and the output signal supplied by the strain gauges is measured as a characteristic for the value of the braking torque. This prior art has the disadvantage (see Column 2, Paragraph 2, of the cited publication) that it can only be used for research and development and troubleshooting purposes.